package com.bookcycle.panda.webfront.util;

import java.security.MessageDigest;
  
import javax.crypto.Cipher;  
import javax.crypto.spec.SecretKeySpec;  

/** 
 * AES���ܣ���Nodejs ����һ�� 
 * @author lmiky 
 * @date 2014-2-25 
 */  
public class AESUtil {  
    public static final String DEFAULT_CODING = "utf-8";  
  
    /** 
     * ���� 
     * @author lmiky 
     * @date 2014-2-25 
     * @param encrypted 
     * @param seed 
     * @return 
     * @throws Exception 
     */  
    private static String decrypt(String encrypted, String seed) throws Exception {  
        byte[] keyb = seed.getBytes(DEFAULT_CODING);  
        MessageDigest md = MessageDigest.getInstance("MD5");  
        byte[] thedigest = md.digest(keyb);  
        SecretKeySpec skey = new SecretKeySpec(thedigest, "AES");  
        Cipher dcipher = Cipher.getInstance("AES");  
        dcipher.init(Cipher.DECRYPT_MODE, skey);  
  
        byte[] clearbyte = dcipher.doFinal(toByte(encrypted));  
        return new String(clearbyte);  
    }  
  
    /** 
     * ���� 
     * @author lmiky 
     * @date 2014-2-25 
     * @param content 
     * @param key 
     * @return 
     * @throws Exception 
     */  
    public static String encrypt(String content, String key) throws Exception {  
        byte[] input = content.getBytes(DEFAULT_CODING);  
          
        MessageDigest md = MessageDigest.getInstance("MD5");  
        byte[] thedigest = md.digest(key.getBytes(DEFAULT_CODING));  
        SecretKeySpec skc = new SecretKeySpec(thedigest, "AES");  
        Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");  
        cipher.init(Cipher.ENCRYPT_MODE, skc);  
          
        byte[] cipherText = new byte[cipher.getOutputSize(input.length)];  
        int ctLength = cipher.update(input, 0, input.length, cipherText, 0);  
        ctLength += cipher.doFinal(cipherText, ctLength);  
              
        return parseByte2HexStr(cipherText);  
    }  
      
    /** 
     * �ַ���ת�ֽ����� 
     * @author lmiky 
     * @date 2014-2-25 
     * @param hexString 
     * @return 
     */  
    private static byte[] toByte(String hexString) {  
        int len = hexString.length() / 2;  
        byte[] result = new byte[len];  
        for (int i = 0; i < len; i++) {  
            result[i] = Integer.valueOf(hexString.substring(2 * i, 2 * i + 2), 16).byteValue();  
        }  
        return result;  
    }  
      
    /** 
     * �ֽ�ת16�������� 
     * @author lmiky 
     * @date 2014-2-25 
     * @param buf 
     * @return 
     */  
    private static String parseByte2HexStr(byte buf[]) {  
        StringBuffer sb = new StringBuffer();  
        for (int i = 0; i < buf.length; i++) {  
            String hex = Integer.toHexString(buf[i] & 0xFF);  
            if (hex.length() == 1) {  
                hex = '0' + hex;  
            }  
            sb.append(hex);  
        }  
        return sb.toString();  
    }  

}  